One advantage of Web based e-mail is that you don't need an account with an Internet Service Provider. All you need is to be able to access the site that runs your e-mail account. You can do this from any computer, anywhere in the world, perhaps a computer at work or by paying to use one at your local library or cyber café. 

The disadvantage is that very  popular Web based e-mail sites can be a victim of their own success. Because they attract so many users, they can be a target for junk mail. This means you may get lots of rubbish in your mail box, although this can happen with any e-mail address.